tag:blogger.com,1999:blog-32847228534759132542018-03-08T07:16:06.708-08:00watermarkMichael Johnsonhttp://www.blogger.com/profile/06537777741792917345noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-3284722853475913254.post-40353091969157375602012-02-09T20:35:00.001-08:002012-02-09T20:35:02.823-08:00<div dir="ltr" style="text-align: left;" trbidi="on">A <b>watermark</b> is a recognizable image or pattern in <a href="http://en.wikipedia.org/wiki/Paper" title="Paper">paper</a> that appears as various shades of lightness/darkness when viewed by transmitted light (or when viewed by reflected light, atop a dark background), caused by thickness or density variations in the paper.<sup class="reference" id="cite_ref-0"><a href="http://en.wikipedia.org/wiki/Watermark#cite_note-0"><span>[</span>1<span>]</span></a></sup> There are two main ways of producing watermarks in paper; the <i>dandy roll process</i>, and the more complex <i>cylinder mould process</i>.<br /> Watermarks vary greatly in their visibility; while some are obvious on casual inspection, others require some study to pick out. Various aids have been developed, such as <i>watermark fluid</i> that wets the paper without damaging it. Watermarks are often used as security features of <a href="http://en.wikipedia.org/wiki/Banknote" title="Banknote">banknotes</a>, <a href="http://en.wikipedia.org/wiki/Passport" title="Passport">passports</a>, <a href="http://en.wikipedia.org/wiki/Postage_stamp" title="Postage stamp">postage stamps</a>, and other documents to prevent <a href="http://en.wikipedia.org/wiki/Counterfeit" title="Counterfeit">counterfeiting</a> (see <a href="http://en.wikipedia.org/wiki/Security_paper" title="Security paper">security paper</a>).<br /> A watermark is very useful in the <a href="http://en.wikipedia.org/wiki/Questioned_document_examination" title="Questioned document examination">examination</a> of paper because it can be used for dating, identifying sizes, mill trademarks and locations, and the quality of a paper.</div>Michael Johnsonhttp://www.blogger.com/profile/06537777741792917345noreply@blogger.com0